Multicast transmissions can be used to deliver a service (e.g., IPTV) from a source to a designated group of recipients (“multicast group”) over a networked environment. The multicast information comprising the service is transmitted from the source once and then copied by network elements (e.g., routers at branches in the network) to deliver the information to each of the recipients in the multicast group. For example, to multicast streaming video from a server to a multicast group serviced by one or more access routers, the server delivers one copy of the streaming video over a network to the access routers. Each of the access routers then copies the streaming video and transmits the streaming video on each path serviced by the access router that reaches a portion of the multicast group. In this way, the portion of the multicast group serviced by an access router will receive the streaming video.
However, congestion control mechanisms are limited for multicast transmissions. Thus, since all recipients in a multicast group receive multicast information addressed to the multicast group at the same bitrate, if a path serviced by an access router that reaches a portion of the multicast group becomes congested, recipients of the portion of the multicast group reached by the congested path can experience service degradation due to packet loss.